Formulation for the control of nematodes

ABSTRACT

In the control of nematodes, use is made of a formulation using D-limonene as a solvent to carry an effective dosage of chloropicrin. The formulation can also include an amount of methyl isothiocyanate corresponding in volume approximately to the amount of chloropicrin. The combination of these two components is synergistic. With the further addition of diazinon, a double synergistic effect is obtained.

BACKGROUND OF THE INVENTION

The present invention is directed to the control of undesirable soil components, and more particularly to the control of nematodes, symphylans wireworms, soil borne diseases, and weed seeds in crop land and ornamental gardens as well as commercial turf. Also included in the undesirable components are mole crickets.

BRIEF REVIEW OF THE PRIOR ART

Nematodes are a good example of undesirable soil components. Nematodes are microscopic eel worms and come in many varities. The dog hookworm is a nematode, i.e., it forms part of the animal parasitic group. But, there are also those forming part of the plant parasitic group. These plant parasitic components feed on plant roots and poisons the plant. They also cause damage to the mammals, including humans who eat the plants. These undesirable soil components have been controled by the injection into the soil of various formulations, one component suggested has been chloropicrin, but this component is very expensive and has not proven too effective, when carried out in practice. The use of chloropicrin has been suggested by Kirk et al, "Encyclopedia of Chemical Technology" in its several editions in the article on Chloropicrin. Nevertheless, in practice, chloropicrin or Cl₃ CNO₂ is not now used in the various commercially avilable formulations except as a warning agent for other fumigants.

Further inhibiting the use of chloropicrin is the tendency of chloropicrin to contaminate such items as beer and soda cans as described in the case of BURKE PEST CONTROL, INC. v. JOSEPH SCHLITZ BREWING COMPANY, 438 So. 2d 95 (Fla. App. 2 Dist. 1983), wherein the brewing company discovered that after a fumigation treatment, from ten to sixty-six nanograms of chloropicrin remained on the can liners which contaminated the cans and made them useless.

Now it has been discovered that the undesirable effects of chloropicrin can be minimized and eliminated by using D-limonene (also called dl-limonene) as a solvent. D-limonene is a material of the terpene family. The terpene family has been most bountiful in providing the means to produce synthetic rubber and other valuable discoveries because of isoprene and the isoprene rule wherein carbon skeletons made of isoprene units are joined in a regular head-to-tail way, repeating the double bonds between molecules or other chemical particles. However, dl-limonene (the "dl" signifying dextro-levo) is a solvent and as such usually does not enhance chemical reaction.

The present invention contemplates the use of D-limonene as a synergistic solvent in connection with the use of agricultural chemicals. Thus, it has now been discovered that a formulation can be provided for the control of nematodes and similar undesirable soil components where the formulation makes use of D-limonene as a solvent for the chloropicrin. Additionally, methyl isothiocyanate can be included in the formulation. Effective amounts of diazinon, if also added will provide a double synergistic effect, the first synergistic effect being the combination of the chloropicrin and D-limonene and the second synergistic effect will be the addition of diazinon.

SUMMARY OF THE INVENTION

Generally speaking the present invention contemplates the following formulations, the amounts being of the order of the quantities shown in parts by weight:

    __________________________________________________________________________     Formulation I                                                                           Formulation II                                                                           Formulation III                                                                          Formulation IV                                    __________________________________________________________________________     83% D-limonene                                                                          70% D-Limonene                                                                           73% D-limonene                                                                           65% D-Limonene                                    17% Chloropicrin                                                                        18% Chloropicrin                                                                         14.5% Chloropicrin                                                                       13% Chloropicrin                                           14% Methyl                                                                               12.5% Diazinon                                                                           10% Methyl Isothiocyanate                                  Isothiocyanate                                                                           12% Diazinon                                                __________________________________________________________________________

DETAILED DESCRIPTION

As used herein, the terms hereinafter listed have the meanings shown next to the particular term:

D-limonene is 4-isopropenyl-1-methyl-1-cyclohexene. The structural formula is: ##STR1## methyl isothiocyanate is CH₂ SCN, being a member of the isocyanate family having the formula R--SCN, where "R" is a hydrocarbon radical

Diazinon is the trade name for phosphorothioic acid. The structural formula is: ##STR2## chloropicrin has the formula Cl₃ CNO₂ and is otherwise known as trichloronitromethane

T is Telone, a Dow Chemical Co. product which is dichloropropene and has the formula: ##STR3## C-17 is also known as Soilex is 17% Chloropicrin, 83% D-limonene C-50 is 50 % chloropicrin, 50% D-limonene

Telone II is 92% dichloropropene

C-17-S is C-17 in a diazinon solution

Vorlex is Telone II plus 20% methyl isothiocyanate

In carrying the invention into practice, various formulations were prepared having about 5 parts by weight and about 80 parts by weight of D-limonene as a solvent into which was added between about 10 parts by weight and about 90 parts by weight chloropicrin, namely, Cl₃ CNO₂, additionally, in some of the formulations there was added about 80 parts by weight to about 20 parts by weight of methyl isothiocyanate. As a further formulation, several batches were prepared containing only D-limonene and methyl isothiocyanate, namely 10 parts by weight to about 50 parts by weight of the methyl isothiocyanate to about 50 parts by weight to about 90 parts by weight of the D-limonene solvent. Also, in some batches diazinon was added in quantities of from zero to about 20 parts by weight.

For the purpose of giving those skilled in the art a better understanding of the invention, the following illustrative examples are given:

Formulations prepared by the applicant herein were tested against formulations of the prior art at several locations in connection with various crops as shown:

(I) Location: Gainesville, Fla., University of Florida Institute of Food and Agricultural Sciences.

Crop: Peanuts; Time August/October 1984

Formulations:

(1) C-17 (hereinbefore described) "SOILEX"

(2) Telone II 1-3-dichloropropane

(3) Vorlex, 1-3-dichloropropane+20% methyl isothiocyonate

The formulation used, namely 17% chloropicrin and 83% D-limonene had a specific gravity of 0.961 or approximately 8 Lbs. per gallon, a boiling point of 112° C., a freezing point of -81° C., a flash point greater than 130° F., vapor pressure at 20° C. of -17 mm Hg. It is almost insoluble in water, soluble in alcohol, petroleum solvents, chlorinated solvents and carbon disulfide. In the presence of water, it becomes corrosive to steel, aluminum, magnesium alloys and vinyl plastics.

(II) Location: Boca Raton, Fla., Boca West Golf Course.

Time: April, 1985

Formulations:

(1) T, Telone (hereinbefore described)

(2) C-17 (hereinbefore described)

(3) C-17-S (hereinbefore described)

(4) C-50 (hereinbefore described)

(5) C-17-D is C-17 as hereinbefore described plus technical DIAZINON (92%)

(III) Location: Tifton, Ga., Costal Plain Experiment Station, Donald Benson Farm, Tift County, Ga.

Crop: Peanuts; Time May/September 1984

Formulations:

(1) T, Telone II

(2) Vorlex

(3) C-17, Soilex

(4) Nemacur

Conclusion, in all the aforementioned tests the formulations described herein namely, D-limonene as a solvent with an effective amount of chloropicrin, and, also by adding an effective amount of methyl-isothiocyanate, and/or with an effective amount of phosphorothioc acid were superior and usually vastly superior to the other formulations shown of the prior art. In the formulations tested, the D-lomonene solvent consist of between about 5 to about 80 parts by weight and the chloropicrin may consist of between about 10 and about 90 parts by weight, the methyl-isothiocyanate component may be from about 20 to about 80 parts by weight, and may include between about zero to about 20 parts by weight of phosphorothioc acid. Another formulation which is effective consists of about 10 to about 50 parts by weight of methyl-isothiocyanate mixed into about 50 to about 90 parts by weight of D-limonene solvent. The combination of chloropicrin and methyl isothiocyanate is synergistic. With the further addition of diazinon, a double synergistic effect is obtained.

    __________________________________________________________________________     EVALUATION OF NEMATICIDES FOR MANAGING THE PEANUT ROOT-KNOT                    NEMATODE ON PEANUT, 1984:                                                                                                  No. nematodes/250 cm.sup.3                                                     soil                                             Methods of appli-             Meloidogyne                                                                             Criconemella              Treatment and overall                                                                        cation & rate per                                                                         Yield %    %   Value/                                                                             arenaria curvatum                  rate per acre (active).sup.X                                                                 100 l. ft. row                                                                            lb/acre                                                                              Damage                                                                              SMK.sup.Y                                                                          acre                                                                               Aug 10                                                                             Oct 9                                                                               Aug                                                                                 Oct                  __________________________________________________________________________                                                               9                    Telone II 15.0 gal                                                                           7 days preplant,                                                                          3,365a.sup.Z                                                                         2    70  $971                                                                               4b  191de                                                                               86bcdefg                                                                            328bcdef                           2-chisels, 10 inches                                                           apart; 65 ml                                                     Telone II 15.0 gal                                                                           14 days preplant,                                                                         3,332ab                                                                              3    69  944 10ab                                                                               211de                                                                               76bcdefg                                                                            276cdef                            2-chisels 10 inches                                                            apart; 65 ml                                                     Vorlex 12.0 gal                                                                              14 days preplant,                                                                         3,174abc                                                                             3    69  917 5ab 793ab                                                                               15fg 138f                               2-chisels, 8 inches                                                            apart.sup.ZZ ; 52 ml                                             Telone II 12.0 gal +                                                                         14 days preplant,                                                                         2,973abcd                                                                            1    74  884 30ab                                                                               110e 103bcdef                                                                            454abc               Temik 15 G 6.0 lb                                                                            2-chisels, 10 inches                                                           apart + at-peg, 14                                                             inch band; 52                                                                  ml + 49 g                                                        Vorlex 12.0 gal +                                                                            14 days preplant,                                                                         2,919abcd                                                                            2    74  863 2b  864a 5g   150ef                Furadan 15 G 6.0 lb                                                                          2-chisels, 8 inches                                                            apart.sup.ZZ + at-peg 14                                                       inch band; 52                                                                  ml + 49 g                                                        Telone II 6.0 gal                                                                            14 days preplant,                                                                         2,842abcd                                                                            2    71  832 38ab                                                                               246cde                                                                              140abc                                                                              196def                             2-chisels, 10 inches                                                           apart; 26 ml                                                     Chloropicrin 6.0 gal                                                                         14 days preplant,                                                                         2,842abcd                                                                            1    73  850 4b  486bcde                                                                             67bcdefg                                                                            453abc                             2-chisels, 10 inches                                                           apart; 26 ml                                                     Untreated Control                                                                            2-chisels, 2,793abcd                                                                            1    61  829 15ab                                                                               620abc                                                                              78bcdefg                                                                            346abcde                           8 inches apart                                                   Untreated Control                                                                            2-chisels, 2,766abcd                                                                            3    64  776 17ab                                                                               367cde                                                                              132abcd                                                                             531a                               10 inches apart                                                  Telone II 12.0 gal                                                                           14 days preplant,                                                                         2,717abcd                                                                            3    69  784 19ab                                                                               307cde                                                                              70bcdefg                                                                            512ab                              2-chisels, 10 inches                                                           apart; 52 ml                                                     Telone II 12.0 gal +                                                                         14 days preplant,                                                                         2,690abcde                                                                           3    69  768 15ab                                                                               229cde                                                                              112bcde                                                                             378abcd              Furadan 15 G 6.0 lb                                                                          2-chisels, 10 inches                                                           apart + at-peg, 14                                                             inch band; 52                                                                  ml + 49 g                                                        Chloropicrin 3.0 gal                                                                         14 days preplant,                                                                         2,624abcde                                                                           1    72  755 9ab 352cde                                                                              59cdefg                                                                             263cdef                            2-chisels, 10 inches                                                           apart; 13 ml                                                     Chloropicrin 9.0 gal                                                                         14 days preplant,                                                                         2,467bcde                                                                            5    55  682 43a 752ab                                                                               78bcdefg                                                                            254def                             2-chisels, 10 inches                                                           apart; 39 ml                                                     Telone II 9.0 gal                                                                            14 days preplant,                                                                         2,467bcde                                                                            8    65  688 26ab                                                                               337cde                                                                              193a 458abc                             2-chisels, 10 inches                                                           apart; 39 ml                                                     Busan 1020 30.0 gal                                                                          14 days preplant,                                                                         2,412cde                                                                             5    68  679 16ab                                                                               576abcd                                                                             40efg                                                                               193def                             2-chisels, 8 inches                                                            apart; 130 ml                                                    Busan 1020 36.0 gal                                                                          14 days preplant,                                                                         2,292de                                                                              5    71  662 37ab                                                                               465bcde                                                                             47defg                                                                              207def                             2-chisels, 8 inches                                                            apart; 156 ml                                                    Soilex C-17 15.0 gal                                                                         14 days preplant,                                                                         2,129de                                                                              6    52  578 10ab                                                                               422bcde                                                                             148ab                                                                               382abcd                            2-chisels, 10 inches                                                           apart; 65 ml                                                     Telone II 15.0 gal                                                                           at-plant, 2-chisels, 10                                                                   1,851e                                                                               3    64  503 6ab 152e 50defg                                                                              502ab                              inches apart; 65 ml                                              __________________________________________________________________________      Peanut (Arachis hypogaea `Florunner`)                                          Rootknot nematode; Meloidogyne                                                 Ring nematode; Criconemella curvatum                                           D. W. Dickson and T. E. Hewlett Dept. Of Entomology & Nematology               University of Florida Gainesville, Florida 32611                               .sup.X Rates calculated for row treatments were reduced from the overall       (broadcast) dosage in proportion to the actual area tested. All dosages        were calculated based on a 36 inch row                                         .sup.Y Sound mature kernels based on government grading system.                .sup.Z Means with the same letter are not significantly different              according to Duncan's new multiple range test (P = 0.05).                      .sup.ZZ Ridged with diskhillers.                                         

    __________________________________________________________________________     BOCA WEST TEST PLOTS                                                           BELONOLAIMUS ONLY                                                              PRE-TEST, 11 DAYS, & 34 DAYS AFTER INJECTION                                   __________________________________________________________________________             SAMPLE NUMBER                                                                             #3         #5    #6                                                 #1   #2    C-17 +                                                                               #4   C-17 +                                                                               C-17 + #7    #8  #9  #10                   NEMATODE                                                                               CHECK                                                                               TELONE                                                                               SAROLEX                                                                              C-17 SAROLEX                                                                              DIAZINON                                                                              TELONE                                                                               C-50                                                                               C-17                                                                               TELONE                __________________________________________________________________________     STING-BELO-                                                                            32   32    24    12   48    52     68    24  60  72                    NOLAIMUS                                                                       PRETEST                                                                        11 DAYS 24   4     20    8    8     12     4     12  4   16                    34 DAYS 52   8     24    8    4     24     28    8   36                        ROOT    NONE 4 new root                                                                           NONE  15 new                                                                              4 new root                                                                           4 new  11 new                                                                               NONE                                                                               4 new                                                                              6 new                 RESPONSE @   11/2" long  root 1" long                                                                              4" long                                                                               3" long   1" long                                                                            11/2" long            11 DAYS                  3" long                                               VISUAL  POOR GOOD 5'                                                                              POOR  POOR POOR  GOOD 6'                                                                               GOOD 8'                                                                              POOR                                                                               POOR                                                                               GOOD 6'               RESPONSE @   of turf                of turf                                                                               of turf       of turf               102 DAYS                                                                       __________________________________________________________________________                         SAMPLE NUMBER                                                                  #11              #14            #17                                            C-17 +                                                                               #12  #13   C-17 + #15 #16 C-17                                                                                 #18                              NEMATODE                                                                               DIAZINON                                                                             CHECK                                                                               C-50  DIAZINON                                                                              C-50                                                                               C-17                                                                               SAROLEX                                                                              CHECK                __________________________________________________________________________                 STING-BELO-                                                                            32    36   36    36     12  16  80    48                               NOLAIMUS                                                                       PRETEST                                                                        11 DAYS 0     48   12    8      16  16  56    28                               34 DAYS 16    4    12    0      0   8   44    84                               ROOT    NONE  NONE NONE  NONE   6 new                                                                              5 new                                                                              NONE  NONE                             RESPONSE @                      3" long                                                                            2" long                                    11 days                                                                        VISUAL  GOOD 8'                                                                              POOR GOOD 5'                                                                              GOOD 20'                                                                              POOR                                                                               POOR                                                                               POOR  POOR                             RESPONSE @                                                                     102 days                                                           __________________________________________________________________________     NEMATODE Three Plot Average Below                                                               CHECK TELONE                                                                               C-17 + S                                                                             C-17  C-17 + D                                                                             C-50                            __________________________________________________________________________                PRETEST                                                                              39    57    51    29    40                                                                                   24                                         11 DAYS                                                                              33                                                                               15%↓                                                                         8                                                                               86%↓                                                                        28                                                                               45%↓                                                                         9                                                                               69%↓                                                                         7                                                                               83%↓                                                                        13                                                                               46%↓                              34 DAYS                                                                              47                                                                               21%↑                                                                         25                                                                               56%↓                                                                        24                                                                               53%↓                                                                        17                                                                               41%↓                                                                        13                                                                               68%↓                                                                        7 71%↓                   __________________________________________________________________________      When the number of nematodes are estimated the following symbols are used      VL--very light infestation;                                                    L--light infestation;                                                          MM--moderate infestation;                                                      H--heavy infestation;                                                          VH--very heavy infestation.                                              

Experiment No. and Title: P5-84. Comparison of Soilex and Telone II applied to peanut 8 days preplant.

Work Unit/Project No.: 7702-20270-001

Address: Coastal Plain Experiment Station, Tifton, GA 31793

Investigator(s): Norman A. Minton and A. S. Csinos

Experiment Location: Donald Benson Farm, Tift, County

Type Experiment: Field

Nematode species: Meloidogyne arenaria, Criconemella ornata

Other Organisms:

Plant species and varieties: Arachis hypogaea, Florunner

Experimental design: Strip

Plot size and No. reps.: 2 rows, 25 ft long, 4 replications.

Soil type: Ocilla loamy soil

Soil moisture: 10.7%, May 2 when chemicals applied

Soil temperature: Maximum, 84 F., minimum, 73 F. at 4" depth when chemicals applied.

Planting dates: May 10

Treatment dates: May 2

Harvest dates: September 24

Weather conditions: Adequate rainfall for good yields

Unusual circumstances:

Progress: See Table P5A-84.

                                      TABLE P5A-84                                 __________________________________________________________________________     Effects of soilex and Telone II applied with the moldboard plow on peanut      production, 1984..sup.1                                                                                              Number nematodes/                                                              150 cm.sup.3 soil,                                                             9/14/84                                                        Root-                                                                              White   Vigor                                                                              Crico-                                                                              Meloido-                            Treatment and                                                                          Method of .sup.2                                                                     Yield                                                                              %   knot                                                                               mold                                                                               Stand                                                                              rating                                                                              nemella                                                                            gyne                                rate (lb ai/A)                                                                         application                                                                          (lb/A)                                                                             SMK.sup.3                                                                          index.sup.4                                                                        hits.sup.5                                                                         (5/21).sup.6                                                                       (6/22).sup.7                                                                        ornata                                                                             arenaria                            __________________________________________________________________________     Telone II 55.8                                                                         A     4857 ab                                                                            80.0                                                                               3.1 a                                                                              3.3 a                                                                              12.0 a                                                                             3.5 b                                                                              2425 a                                                                              530.0 a                             Soilex 117.6                                                                           A     5162 a                                                                             79.7                                                                               3.9 a                                                                              3.3 a                                                                              12.0 a                                                                             4.3 ab                                                                             1545 a                                                                              422.5 a                             Control       4552 b                                                                             78.7                                                                               5.9 a                                                                              4.8 a                                                                              13.3 a                                                                             4.5 a                                                                              2052 a                                                                              1475.0 a                            __________________________________________________________________________      .sup.1 Data within same column followed by the same letter are not             significantly different (P = 0.05) according to Duncan's multiplerange         test.                                                                          .sup.2 Applied in moldboard plow furrow 10"  deep on 8" centers 8 days         before planting.                                                               .sup.3 % sound mature kernel (SMK) determined from composit sample from        four replications.                                                             .sup.4 Rootknot index based on rating of 0-10: 0 = no galling, 10 = 100%       of roots and pods galled.                                                      .sup.5 White mold hits = number of hits per 50 ft row. One or more plants      infected per ft of row in one hit.                                             .sup.6 Stand = number of plants emerged per m of row.                          .sup.7 Vigor rating based on scale of 1-5: 1 = poor growth, 5 = excellent      growth.                                                                  

Experiment No. and Title: P6-84. Fumigant nematicides: Methods of application to peanut 8 days preplant.

Work Unit/Project No.: 7702-20270-001

Address: Coastal Plain Experiment Station, Tifton, GA 31793

Investigator(s): Norman A. Minton and A. S. Csinos

Experiment Location: Donald Benson Farm, Tift County

Type Experiment: Field

Nematode species: Meloidogyne arenaria, Criconemella ornata

Other Organisms:

Plant species and varieties: Arachis hypogaea, Florunner

Experimental design: Strip

Plot size and No. reps.: 2 rows, 25 ft long, 4 replications

Soil type: Ocilla loamy soil

Soil moisture: 10.7% May 2 when fumigant nematicides applied.

Soil temperature: Maximum, 84 F.; minimum, 73 F. at 4" depth when the chemicals applied.

Planting dates: May 10

Treatment dates: Fumigants, May 2; Nemacur, May 10

Harvest dates: September 24

Weather conditions: Adequate rainfall for good yields

Unusual circumstances:

Progress: See Table P6-84.

                                      TABLE P6A-84                                 __________________________________________________________________________      Effects of three fumigant nematicides applied with                            moldboard plow and single chisel on peanut production, 1984..sup.1                                                    Number nematodes/                                                              150 cm.sup.3 soil,                                                             9/14/84                                                        Root-                                                                              White   Vigor                                                                              Crico-                                                                              Meloido-                           Treatment and                                                                           Method of.sup. 2                                                                     Yield                                                                              %   knot                                                                               mold                                                                               Stand                                                                              rating                                                                              nemella                                                                            gyne                               rate (lb ai/A)                                                                          application                                                                          (lb/A)                                                                             SMK.sup.3                                                                          index.sup.4                                                                        hits.sup.5                                                                         (5/21).sup.6                                                                       (6/22).sup.7                                                                        ornata                                                                             arenaria                           __________________________________________________________________________     Telone II 37.2                                                                          A     4640 ab                                                                            76.7                                                                               4.3 bc                                                                             3.0 b                                                                              12.4 a                                                                             2.5 bc                                                                             3097 a                                                                              932.5 b                            Vorlex 38.4                                                                             A     2975 c                                                                             74.0                                                                               9.5 a                                                                              18.0 a                                                                             13.3 a                                                                             2.3 c                                                                              1652 bc                                                                             2297.5 a                           Telone II 37.2                                                                          B     4852 ab                                                                            79.7                                                                               2.9 cd                                                                             3.3 b                                                                              11.6 a                                                                             3.5 a                                                                              2782 ab                                                                             435.0 b                            Vorlex 38.4                                                                             B     4360 b                                                                             76.0                                                                               3.4 cd                                                                             3.8 b                                                                              11.9 a                                                                             3.0 a-c                                                                            1702 a-c                                                                            522.5 b                            Soilex CP 39.2                                                                          B     4476 b                                                                             78.3                                                                               4.1 bc                                                                             3.0 b                                                                              11.3 a                                                                             3.0 a-c                                                                            2597 ab                                                                             700.0 b                            Nemacur 15 G 2.5                                                                        C     5064 a                                                                             78.7                                                                               1.4 d                                                                              3.3 b                                                                              11.6 a                                                                             3.3 ab                                                                             667 c                                                                               470.0 b                            Control        4325 b                                                                             77.0                                                                               6.2 b                                                                              3.5 b                                                                              12.9 a                                                                             3.3 ab                                                                             1350 bc                                                                             1135.0 b                           __________________________________________________________________________      .sup.1 Data within same column followed by the same letter are not             significantly different (P = 0.05) according to Duncan's multiplerange         test.                                                                          .sup.2 Method of application: A = applied in moldboard plow furrow 10"         deep spaced 8" apart 8 days before planting, B = injected 10" deep in row      with single chisel 8 days before planting, C = applied in 12" band over        row, rototilled 2" deep at plant.                                              .sup.3 % sound mature kernel (SMK) determined from composit sample from        four replications.                                                             .sup.4 Rootknot index based on rating of 0-10: 0 = no galling, 10 = 100%       of roots and pods galled.                                                      .sup.5 White mold hits = number of hits per 50 ft row. One or more plants      infected per ft of row is one hit.                                             .sup.6 Stand = number of plants emerged per m of row.                          .sup.7 Vigor rating based on scale of 1-5: 1 = poor growth, 5 = excellent      growth.                                                                   

What is claimed is:
 1. A nematocidal agricultural formulation for the control of nematodes consisting essentially of a D-limonene solvent and between 15% and 20% of chloropicrin, the percentage being by weight.
 2. A method of controlling nematode infestation comprising applying to said nematodes or the habitate thereof a composition consisting essentially of a D-limonene solvent and between 15% and 20% by weight of chloropicrin. 